A crossbow is a kind of sports facilities with extremely strong firing force, of which the firing mechanism includes mainly a trigger system and bowstring and wherein the trigger system is the crucial control device when shooting. Accordingly, the security, the operability and the maintainability of the triggering system might directly affect the efficiency and the safety of the crossbow. The present trigger system adopted in the market is configured as a whole body and it is exceedingly difficult to be assembled or disassembled. Consequently the trigger system is very hard to be maintained and well-used. In addition, a safety device on the crossbow itself is mainly used in order to prevent the arrow from being launched by mistake. However, the effective protection is deficient for the trigger system. Once the safety device on the crossbow itself is broken down or operated by mistake, it will cause error shooting/launching of the arrow and then reduce the safety when using the crossbow.
On the other hand, the arrow always drops off easily due to the restriction of the operating angle and the faulty operation when using the crossbow. Furthermore, even if the arrow is dropped off or is not installed correctly, the shooting of the crossbow is still capable of being performed and it leads to empty shooting accordingly. Although the empty shooting is not harmful to the crossbow body and the user, it will reduce greatly the using efficiency.